<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">
        function draw() {
            var canvas = document.getElementById('canvas');
            if (canvas.getContext){
                var ctx = canvas.getContext('2d');

                //三次贝塞尔曲线
                ctx.beginPath();
                ctx.moveTo(75,40);
                ctx.bezierCurveTo(75,37,70,25,50,25);
                ctx.bezierCurveTo(20,25,20,62.5,20,62.5);
                ctx.bezierCurveTo(20,80,40,102,75,120);
                ctx.bezierCurveTo(110,102,130,80,130,62.5);
                ctx.bezierCurveTo(130,62.5,130,25,100,25);
                ctx.bezierCurveTo(85,25,75,37,75,40);
                ctx.fill();
            }
        }
    </script>
</head>
<body>
<body onload="draw()">
<canvas id="canvas" width="150px" height="150px"></canvas>
</body>
</body>
</html>